A NFT Item can be
An image is a unique file like a piece of art, a picture, profile, etc. Formats are .png, .jpg or .gif
Is a recording, animation, short movie, etc. For videos you can choose multiple files, but all files should correspond to same asset with different format, i.e. .mp4 and .ogv. This is because some video formats are more suitable than others on different devices.
A song, podcast, effects, etc. You can choose multiple files, but all files should correspond to same asset, i.e. .mp3 and .ogg.
This is a unique file that correspond to a property, license, loan, debt or any other document you need.
GLB Interactive 3D models are supported